On November 6, public service announcements reminded us to “fall back,” ending daylight saving time (DST) by setting our clocks an hour earlier. On November 7, many of us commuted home in the dark.

This semiannual ritual shifts our rhythms and temporarily makes us groggy at times when we normally feel alert. Moreover, many Americans are confused about why we spring forward to DST in March and fall back in November, and whether it is worth the trouble.

This year I was invited to give the keynote address at Passive HouseA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates. Alliance China’s 3rd China Passive Building Summit in Shanghai, with the explicit request to report on passive building progress in the U.S. and on PHIUS’ climate-specific standards.

In light of the immense amount of development currently taking place in China, with whole cities springing up practically overnight and a huge stock of existing buildings in need of energy efficiency upgrades, China’s interest in the passive building work being done in the U.S. is significant.

Peer Diffusion: A form of communication within and between networks of people that (1) occurs through varying forms of social comparison and social interaction around an innovation (i.e., a new behavior, idea, or technology) and (2) ultimately promotes the broader adoption of that innovation.

Editor's note: David and Kayo Murakami Wood are building what they hope will be Ontario's first certified Passive HouseA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates. on Wolfe Island, the largest of the Thousand Islands on the St. Lawrence River. They are documenting their work at their blog, Wolfe Island Passive House. For a list of earlier posts in this series, see the sidebar below.

Ever since the 1973 oil embargo, U.S. energy policy has sought to replace petroleum-based transportation fuels with alternatives. One prominent option is using biofuels such as ethanol in place of gasoline and biodiesel instead of ordinary diesel.

Transportation generates one-fourth of U.S. greenhouse gas emissions, so addressing this sector’s impact is crucial for climate protection.

Because zero-energy homes are built to higher standards than most ordinary homes, they require greater attention to detail and often cost somewhat more. These two realities make zero energy homes especially well suited to the economies of scale, the speed of construction, and the precision industrial methods involved in modern prefab construction.

Over the past 20 years, the building industry has experienced renewed interest in reducing the energy demand of buildings. At the building code level, groups such as the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAEAmerican Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).
International organization dedicated to the advancement of heating, ventilation, air conditioning, and refrigeration through research, standards writing, publishing, and continuing education. Membership is open to anyone in the HVAC&R field; the organization has about 50,000 members.
) have been steadily raising the bar on performance criteria for building envelopes and systems. Designers have been challenged to find and implement technologies and solutions that can practically and economically affect the energy demands of our buildings.

A few months ago we completed a deep energy retrofit of a house that we hope will be net-zero energyProducing as much energy on an annual basis as one consumes on site, usually with renewable energy sources such as photovoltaics or small-scale wind turbines. — in other words, that we hope will produce as much energy as it consumes on an annual basis. If we succeed, this will be our first net-zero project.

There are two key strategies for designing a net-zero-ready home: you minimize the amount of energy the house needs to operate; and you maximize the amount of energy that the house can produce onsite, usually with a photovoltaic(PV) Generation of electricity directly from sunlight. A photovoltaic cell has no moving parts; electrons are energized by sunlight and result in current flow. system (PVPhotovoltaics. Generation of electricity directly from sunlight. A photovoltaic (PV) cell has no moving parts; electrons are energized by sunlight and result in current flow.). In short, you create an energy budget that balances consumption with production.

The soul of Arizona State University is Memorial Union, a hulking brick-and-glass community center that opens onto a sprawling pedestrian mall. Although the building sits at the heart of campus, its outdoor plaza was once virtually uninhabitable for four months each year, when summer temperatures in scorching Tempe often hover over 100 degrees.

So in 2014, the university — Arizona’s leading energy consumer — completed construction on a PowerParasol, a 25-foot-tall shade canopy composed of 1,380 photovoltaic(PV) Generation of electricity directly from sunlight. A photovoltaic cell has no moving parts; electrons are energized by sunlight and result in current flow. panels capable of producing 397 kilowatts of electricity.

Sam Rashkin is a man with a mission: a mission no less ambitious than to change the way American homebuilders conceive, construct, and promote their products.

As the father of the Energy StarLabeling system sponsored by the Environmental Protection Agency and the US Department of Energy for labeling the most energy-efficient products on the market; applies to a wide range of products, from computers and office equipment to refrigerators and air conditioners. Certified Homes Program, and now as chief architect of the building technologies office at the U.S. Department of Energy, his day-job description involves promoting super-energy-efficient construction. As a designer with businessman’s heart, he prefers to call it high performance construction.